1. Field of the Invention
This invention pertains generally to power line communications, and more particularly to an apparatus and method of establishing a compatible network key for encrypting and decrypting communications between streaming media devices communicating over a PLC network.
2. Description of Related Art
The convenience of Power Line Communication (PLC) systems combined with the increased availability of off-the-shelf PLC circuitry is leading to rapid deployment in a number of consumer and business market segments. PLC is a network technology in which consumer electronics devices are networked over conventional AC power connections. Recent enhancements in the available bandwidth has widened applications for PLC into streaming media (i.e., audio and video) networking arenas.
FIG. 1 depicts a basic configuration 10 of a streaming media PLC network. A streaming media server device 12 is shown coupled to streaming media client devices 14, 16 through a PLC network 18. Server 12, such as a personal computer 20 adapted for executing a PLC network server application, provides for storing streaming media content, receiving various broadcast, cable, satellite, or media based programming, and transmitting media streams over power line 18. Clients 14, 16 may comprise any device configured for receiving or transmitting audio and/or video content through the PLC network, although they may also communicate content by other means as well, such as line-in, line-out connections, and so forth. Clients 14, 16 are depicted as video monitors or television sets 22, 24, however, it should be appreciated that clients may comprise video/audio playback or recording devices, cameras, audio recording equipment, audio systems, video monitors, television systems, control panels, monitoring devices, alarm control equipment, and so forth.
One principle advantage of PLC networking is that a separate network connection between server 12 and clients 14, 16 need not be established, because the devices are already coupled through the common AC power line from which they draw operating power. The PLC network connectivity is thus a flexible arrangement in which all devices can join the network in response to simple connection of a power plug 26 into the power outlet 28. Although a two prong power plug 26 is shown for the sake of simplicity, it should be appreciated that any desired power plug configuration can be supported, for example the use of any two, three or four conductor power connections which may be required for a given region, or type of power distribution arrangement. Despite the numerous advantages described, PLC networks suffer from security issues.
FIG. 2 depicts a common PLC network scenario 30 in which the power line 32 is shared between a first site 34 (e.g., home, office, business, industry, and so forth) and a second site 36. In this case two similar homes 34, 36 are shown each having PLC-based equipment, exemplified as servers 38, 42 and clients 40, 44. It will be appreciated that in residential settings five or more homes may share the power lines extending from a given transformer. Accordingly, the data communicated over the PLC network within one home could be captured on the PLC network within the other homes, wherein security becomes a concern.
In attempting to overcome this security issue the content being shared over the PLC network by a given entity is preferably communicated in an encrypted (scrambled) form and decrypted (de-scrambled) after receipt. Decrypting the communication requires that the device be provided with a decryption key that is utilized by the decryption routines (or circuits) for adjusting decryption operations to match the encryption which was performed. All the devices utilizing the PLC network must share the same network key in order to communicate with one another.
Although content encryption-decryption can provide security it is often troublesome to provide and share a decryption key. One method of establishing the encryption-decryption network key is for the user to manually enter a network key value for the device. However, the key can comprise a long series of digits making entry difficult, while not every client device is necessarily configured with a keypad or sufficiently adept user interface to readily allow entry of the key. In addition, manual entry of the decryption key adds another level of complexity to utilizing PLC network communication. The security key could be shared over the PLC network itself, but this could also allow external devices of other entities to capture the key thus compromising security. Utilizing manual entry security keys would undoubtedly frustrate users while subjecting manufacturers to a high volume of service calls arising from improper entry or use of the network keys. In addition, one must consider the problems which would arise when periodically updating a security key to increase privacy protection.
Accordingly, a need exists for a system and method of securing a power line communication (PLC) network while overcoming the problems with an entity sharing network keys with other streaming media devices on its portion of the PLC network. These needs and others are met within the present invention, which overcomes the deficiencies of previously developed methods of maintaining common network keys.